Decorative boards or panels are conventionally used as interior baseboards, wainscots, decoration panels, etc. Conventionally there is a decorative board comprising a plastic (such as acrylic or polyvinyl chloride) substrate and a patterned paper or sheet, which are thermo-compression bonded together. Such conventional boards provide certain optical transmittance and are widely used, e.g., as flooring, ceiling, wall or light shielding materials. There is also a glass board for use, e.g., as a table top or shelf board, comprising a plastic film and a solid or thick (often as thick as 5 mm or over) glass board, which are bonded together.
A relatively fragile conventional decorative board is liable to cracking or flaws and therefore generally unfit for use as a shelf board or table top which requires considerable resistance against physical shocks and/or pressing force. A relatively solid and sturdy conventional glass board comprising a glass board and a plastic film is relatively hard to process such as cutting and often excessively heavy to handle.
Accordingly, it is a “first” object of the present invention to provide a decorative board which is translucent or semitransparent, lighter than glass, easy to process, resistant to cracking and flawing, and excellent in overall mechanical properties.
A single-color board is disclosed in JP Patent Publication No. 5-39187, which comprises a substrate board containing a polymeric pigment, which is sandwiched by identically colored sheets. This decorative board material is not sufficiently translucent and thus is not particularly suitable for use against a light source.
The inventors of the present invention originally aimed at providing a translucent or semi transparent decorative board by directly coloring a polymeric substrate. However, such a translucent decorative board posed a number of problems. Some of the major problems are a) difficulty in controlling colors; b) relatively limited colors as a result of manufacturing restrictions; c) requirement of a large manufacturing plant; d) relatively low productivity; e) unfitness for small quantity production; and f) relatively poor mechanical properties.
Accordingly, it is a “second” object of the present invention to provide an “evenly-colored” decorative board which can be economically produced even in a small quantity, where its transparent substrate and colored cover layers together provide an “illusion” of an evenly colored board.
There also conventionally exists a translucent (semitransparent) decorative board for use as a window pane, door board or illumination shade, comprising a transparent substrate such as a glass board and a colored or patterned fabric or plastic sheet bonded to the transparent substrate. Such a conventional decorative board is short of providing “special” effects or satisfactory transparency.
Accordingly, it is a “third” object of the present invention to provide a decorative board or pane which provides “fancy” transparency or translucency as well as soothing effects on viewers' mental states.
Other objects of the present invention will become apparent from the following descriptions.